Glow lamp



June l0, 1930.

P. L. SPENCER @Low LAMP Filed March 1, 1929 Patented June 10, 1930 UNITED STATES .PATENT lori-"Ica PEBCY L. SPENCER, OF MEDFORD, MASSACHUSETTS, ASSIGNOR, BY MESNE ASSIGN- MENTS, TO 011D COLONY TRUST COMPANY, A CORPORATION OF MASSACHUSETTS GLOW Application led March 1,

This invention relates to glow lamps and especially to that type of lamp which 1s capa le of translating rapid current variatlons into light variations for use in televlsion systems, recording systems, and the like. In certain television systems, it is desirable that Athe source of glow be shifted from one spot to another with extreme rapidity. To accomplish this, a glow lamp has beenused having a plurality of separately connectedelectrodes placed in a line and cooperating with a common electrode. These electrodes were generally small flat pieces of metal disposed in a line and in the same lane and cooperating with a common wire. y impressing suitable potential between any one or more of these small electrodes and the wire, a glow discharge was initiated between the two. In order to shift the discharge, a commutating switch rapidly changed the connections in proper sequence.

One of the objections to this type of lamp was that the separate glow discharges were not sufficiently isolated from each other to render each one distinct. Furthermore, such a device had a high starting potential and a comparatively short useful life.

An object of my invention is to devise a glow lamp in which the above disadvantages are substantially eliminated. Referring to the drawings, Figure 1 is a sectional view in elevation of a tube embod ing my invention.

Figure 2'is a side view t ereof.

Figure 3 is a sect-ion on line 3-3 of Figure 2.

Figure 4 is a detailed view.

Referring to the drawings, 1 is a glass container having inwardly projecting press 2 in which are sealed the various electrodes. Sealed at the intermediate portion of the press are anodes 4 and 5. Preferably these are' made of straight heavy nickel wire. Surrounding wires 4 and 5 are tubular members 6 and 7 integral with the press. Maintaining anodes 4 and 5 in predetermined relation to LAMP 1929. Serial No. 343,680.

tubular members 6 and 7 are insulators 8 and 9 of lava or any similar material. These insulators have reduced cylindrical portions 10 and 11 which snugly fit into tubular members 6 and 7.. The upper portions of insulators 8 and 9 have shoulders 12 and 13. Suitabl supported on insulators 8 and 9 is a cat ode structure shown in detail in Figure Retaining these two members 15 and 17 in spaced relationship is a cylindrical member 18. As is shown in the drawing, member 18 engages members 15 and 17 at their upturned edges and is welded thereto. Member 18 is just long enough so that an opening 19 gives access to the interior. Shoulders 12 and 13 of insulators 8 and 9 are thus engaged by the annular channel in member 15 and tend to firmly retain the entire cathode structure. rllhe distance between the edges 16 of the cathode and anodes 4 and 5 is preferably of the order of the mean free path of the gas used in the tube. In this way, eii'ective insulation is obtained between opposing electrodes near the insulators whereby destruction of the latter is avoided. Engaging the annular channel in the top member 17 of the cathode are insulators 20. These insulators are cylindrical and have upstanding shoulders on both sides similar to shoulders 12 and 13 of insulators 8 and 9. These insulators are the same on both sides and hence, may be used interchangeably. A-cathode structure similar to the one below the insulators 20 is disposed above these insulators in the same manner. Other insulators and cathode are successively built up in this manner. The top closes the cathode.

In order to furnish suitable support for the structure as well as electrical connections therefor, supporting wires 30, 31, 32, 33, and 34 are sealed in press 2. These wires are welded to the respective cathode, the last two being welded to the top cathode. Wires S30-33 inclusive are suitably welded to leads which go to suitable connections in a base shown in dotted lines.

The cathodes may be of any suitable metal such as nickel, molybdenum, or tantalum and are preferably treated so that copious electron emission is obtained therefrom. The entire tube is suitably exhausted and freed of ccluded gases and then lled with a mixture of any one or more gases or vapor, preferably the rare gases. A mixture of 85% helium and 15% neon is especially desirable and may be Y used at a pressure between and 10 mm.

20 Upon the application of suitable potential between anodes 4 and 5 which are connected together and any one or more of the cathodes, an intense and highly actinic glow will be visible through the corresponding apertures 19. By connecting the cathodes in any desired sequence and at any desired speed, the glow may be rapidly and easily shifted from any one to any other cathode.- Such a glow is capable of rapidly and faithfully following current variations.

While I have shown the cathode chambers as having circular cross sections, it is obvious that my invention is not limited thereto. As many cathodes as may be desired may be dis 35 posed in any manner whatsoever, either vertically or horizontally or even circularly. Instead of two anodes, I may use one anode or more than two.

I claim:

1. A glow lamp comprising a plurality of separate electrodes and a common electrode enclosed by all of said electrodes.

2. A glow lamp comprising a plurality of separately connected cathodes and an anode enclosed by all of said cathodes.

3. A glow lamp comprising a plurality of cathode chambers, each of said chambers comprising a cathode having its interior surface to promote electron emission therefrom, each of said cathodes being insulated from the others and a common anode substantially enclosed by said cathodes.

4. A glow lamp comprising a wire anode and a plurality of cathodes built around said anodes, each of said cathodes being insulated from the remaining cathodes and having an opening whereby the interior discharge is visible.

5. A glow lamp comprising a plurality of electrodes, a common electrode enclosed by said other electrodes, each of said other electrodes and said common electrode adapted to have a discharge between the interior surface g5 of said other electrodes and said common electrode and means for rendering said discharge visible.

6. A glow lamp comprising an evacuated container, a press, a wire anode sealed in said press, a plurality of hollow cathodes built around said wire anode, each of said cathodes being insulated from the remaining cathodes, said cathodes having slits through which the interior discharge may be Viewed.

In testimony whereof, I have signed my name to this specification.

PERCY L. SPENCER.

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